public void SignUp_InvalidRequest_RespondsWithValidationErrors() { var request = new TeacherTrainingAdviserSignUp { Email = "invalid-email@" }; _controller.ModelState.AddModelError("Email", "Email is invalid."); var response = _controller.SignUp(request); var badRequest = response.Should().BeOfType <BadRequestObjectResult>().Subject; var errors = badRequest.Value.Should().BeOfType <SerializableError>().Subject; errors.Should().ContainKey("Email").WhichValue.Should().BeOfType <string[]>().Which.Should().Contain("Email is invalid."); }